
struct book{
       int num;
       char aut[100];
       }b[200000];
int count[1000]={0};

int main()
{
    int n,max=0,maxnum,i,j,f;
    scanf("%d", &n);
    for(i=1;i<=n;i++){
                      scanf("%d %s", &b[i].num, b[i].aut);
                      for(j=0;j<strlen(b[i].aut);j++){count[b[i].aut[j]]++;}
                      }
    for(i='A';i<='Z';i++){
                         if(count[i]>max){
                                          max=count[i];
                                          maxnum=i;
                                          }
                         }
    printf("%c\n%d\n", maxnum, max);
    for(i=1;i<=n;i++){
                      f=0;
                      for(j=0;j<strlen(b[i].aut);j++){
                                                      if(b[i].aut[j]==maxnum){f=1;}
                                                      }
                      if(f==1){printf("%d\n", b[i].num);}
                      }

    return 0;
}

